In honor of November’s National Pet Cancer Awareness Month I would like to share some “hot off the press” wonderfully optimistic news with you. Dr. Nicola Mason from the University of Pennsylvania School of Veterinary Medicine has been researching a new way to treat osteosarcoma, an aggressive and fatal form of bone cancer that has an affinity for growing within the leg bones of large and giant- breed dogs.

Until now, treatment of osteosarcoma has consisted primarily of amputation (removal) of the affected leg with or without chemotherapy. In spite of such aggressive treatment, inevitably tiny clusters of cancer cells eventually grow into metastatic tumors that ultimately become life-ending. Approximately 60% of dogs die within one year of the diagnosis.

A new approach

Dr. Mason’s innovative approach to treating dogs with osteosarcoma involves “cancer immunotherapy” in which the patient’s own immune system is triggered to target and kill tumor cells. In order to use a dog’s immune system to treat osteosarcoma Dr. Mason devised a vaccine consisting of bacteria that have been modified to express a protein called Her2/neu. This protein is known as a “growth factor receptor” and is found on a variety of different cancer cells, including some canine osteosarcoma cells. You may have heard of Her2/neu before because it is commonly associated with breast cancer cells in women. The concept behind the vaccine is as follows: The bacteria stimulates the dog’s “immune system soldiers” to seek out and destroy the bacteria along with cells that express Her2/neu (osteosarcoma cells).

Outcomes to date

Thus far, Dr. Mason has treated 12 dogs with osteosarcoma following amputation and chemotherapy. The dogs received the vaccine once weekly for three weeks. Side effects of the vaccine were minimal. All that was observed was a mild, brief fever following vaccine administration.

The preliminary results have been immensely encouraging. The first vaccinated dog, Sasha has a survival time of 570 days thus far. Two other dogs vaccinated at the beginning of the study are alive and cancer free more than 500 days post diagnosis. Other dogs who were vaccinated more recently are still doing well. These are truly fantastic results.

What comes next?

Some dogs with osteosarcoma are not good candidates for amputation primarily because of neurological or musculoskeletal issues in their other limbs. Treatment options for these dogs are aimed at reducing the pain associated with the tumor. Dr. Mason plans to begin including some of these nonsurgical candidates in her osteosarcoma vaccine study.

Additionally, Dr. Mason is contemplating learning if what she has developed would be an effective means for prevention of osteosarcoma. Certain breeds (Rottweilers, Irish Wolfhounds, Great Danes, Saint Bernards, Doberman Pinschers, and Greyhounds, to name a few) are particularly predisposed to osteosarcoma. It will be fascinating to learn if the osteosarcoma vaccine will effectively prevent this horrific disease in high-risk individuals.

The research results gathered thus far represent a monumental success in cancer treatment and provide significant hope for a disease previously associated with a grim prognosis. Kudos to Dr. Mason for her stunning work! If your dog has osteosarcoma and you are interested in participating in Dr. Mason’s studies, contact her at 215-898-3996 or by e-mail at nmason@vet.upenn.edu.

If you would like to respond publicly, please visit Speaking for Spot.
Best wishes,
Nancy Kay, DVM

Diplomate, American College of Veterinary Internal Medicine
Author of Speaking for Spot: Be the Advocate Your Dog Needs to Live a Happy, Healthy, Longer Life
Author of Your Dog's Best Health: A Dozen Reasonable Things to Expect From Your Vet
Recipient, Leo K. Bustad Companion Animal Veterinarian of the Year Award
Recipient, American Animal Hospital Association Animal Welfare and Humane Ethics Award
Recipient, Dog Writers Association of America Award for Best Blog
Recipient, Eukanuba Canine Health Award
Recipient, AKC Club Publication Excellence Award
Become a Fan of Speaking for Spot on Facebook

Please visit http://www.speakingforspot.com to read excerpts from Speaking for Spot and Your Dog's Best Health. There you will also find "Advocacy Aids"- helpful health forms you can download and use for your own dog, and a collection of published articles on advocating for your pet's health. Speaking for Spot and Your Dog's Best Health are available at www.speakingforspot.com, Amazon.com, local bookstores, and your favorite online book seller.